This invention relates generally to improvements in the fabrication of actuator assemblies for use in computer disk drives. More particularly, this invention relates to an improved actuator assembly and method for attaching a coil assembly to an actuator in a manner which economically and reliably assures proper alignment of the coil assembly.
In recent years, microcomputer equipment, particularly the so-called personal and desk top computers, have become extremely popular for a wide variety of business, educational and other uses. Such computers commonly include a main central processor unit having one or more memory storage disks for storage of data. In many modern computers the storage disk or disks sometimes referred to as "hard disks," are provided as part of a Winchester-type disk drive unit having the storage disks supported in a stack on a rotary spindle within a substantially sealed disk drive housing. The disks are rotatably driven in unison by a small spindle motor, and one or more electromagnetic heads on a movable actuator are displaced by a moving coil, limited rotation D.C. motor to traverse surfaces of the rotating disks for purposes of reading and writing data. Such Winchester-type disk drive units are generally preferred in comparison with so-called floppy-type disk drives due their higher memory storage capacities and faster operating speeds.
The actuator used in Winchester-type disk drive units resembles the traversing arm of a common phonograph, and is pivotally mounted about a shaft adjacent an edge of the stacked storage disks. Such actuators typically include an arm assembly designed to carry the electromagnetic heads which are used to read and write data on the disk stack, and a counterbalance situated opposite the arm assembly with respect to the pivot shaft.
A coil is mounted to the counterbalance portion of the actuator to interact with a magnet assembly, for purposes of controlling the movement and positioning of the electromagnetic heads. As a current moves through the coil, it reacts with the magnet assembly to move the entire actuator assembly, comprising the actuator and the coil. Since precision control of the armature is necessary for proper operation of the disk drive unit, accurate positioning of the coil with respect to the actuator is critical to satisfactory performance.
The need for precision components in disk drive units often conflicts with the desire by manufacturers to produce products in an efficient and reliable manner. For example, in order to manufacture actuator assemblies to proper specifications and tolerances, the actuator and the coil assembly are typically fabricated separately and then attached to one another prior to installation into the disk drive unit. The precision relationship between the actuator and the coil assembly has previously required, however, an unacceptable degree of manual-type work during the assembly process. This has resulted in reduced economy of manufacture, higher costs and less than desirable levels of unit reproducibility.
Accordingly, there has been a need for an improved actuator assembly and method for attaching a coil assembly to an actuator in a manner which economically and reliably assures proper alignment of the two elements prior to installation into a disk drive unit. Such an improved actuator assembly should include components easily attached to one another, and which can be properly aligned quickly, locked into position and secured together utilizing a minimal number of steps. Further an improved actuator assembly and related method of fabrication is needed which minimizes the possibility of human-introduced error during the assembly process which could result in misalignment of the coil with respect to the actuator. Moreover, such an improved actuator assembly must be capable of prolonged, reliable use, and accommodate additional elements incorporated into disk drive units. The present invention fulfills these needs and provides other related advantages.